If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

The Past 5,000 Years Mark a New Epoch in Human Evolution

"We are more different genetically from people living 5,000 years ago than they were different from Neanderthals."

...

A team led by University of Wisconsin-Madison anthropologist John Hawks estimated that positive selection just in the past 5,000 years alone -dating back to the Stone Age - has occurred at a rate roughly 100 times higher than any other period of human evolution. Many of the new genetic adjustments are occurring around changes in the human diet brought on by the advent of agriculture, and resistance to epidemic diseases that became major killers after the growth of human civilizations.

...

In the hunt for recent genetic variation in the genome map the project has cataloged the individual differences in DNA called single nucleotide polymorphisms (SNPs). The project has mapped roughly 4 million of the estimated 10 million SNPs in the human genome. Hawks' research focuses on a phenomenon called linkage disequilibrium (LD). These are places on the genome where genetic variations are occurring more often than can be accounted for by chance, usually because these changes are affording some kind of selection advantage.

The researchers identify recent genetic change by finding long blocks of DNA base pairs that are connected. Because human DNA is constantly being reshuffled through recombination, a long, uninterrupted segment of LD is usually evidence of positive selection. Linkage disequilibrium decays quickly as recombination occurs across many generations, so finding these uninterrupted segments is strong evidence of recent adaptation, Hawks says.